Monday, 15 September 2008

We (physicists) like to discuss our favorite theories. We like to compare and contrast them. We like to loudly proclaim which ones we think are crap, which ones have a chance at being right, and which ones we're pretty sure are right. This is lunchroom conversation that the public generally isn't privy to. In fact, most people have never heard of the theories we are arguing about.

If you run across a theory, in a news report, web page, blog, or even the arXiv (beware the physics/ section), how is one to know what is crap and what is not? Well first of course, one should visit John Baez' Crackpot Index before believing "the uncertainty principle is untenable!" But what about after that?

Science is built upon consensus. However, the media often portrays scientific issues by presenting two opposing viewpoints. Sometimes, one viewpoint is held by 99.9% of scientists, and the other viewpoint is held by just one guy. The public, unaware of who is the scientist and who is the crackpot here, comes away with the idea that both ideas are reasonable, that there's a real debate, and 50% of the public ends up falling for some idea that is completely false. (For instance, global warming deniers, or that tobacco doesn't cause cancer, or that the LHC somehow presents some kind of danger to the continued existance of mankind) This mode of reporting does a huge disservice to the truth, and truly harms science in particular. At least in America, investigative reporting is all but dead. We're supposed to decide for ourselves now.

Scientific consensus is only reached after a significant amount of time has passed, and the experiments and theories have been absorbed into the minds of the practitioners of science. This consensus is really all the public needs to worry about. Sure we have our internal conflicts and arguments, but it's like seeing how sausage or laws are made. The public doesn't really want to see it, they just want to know what answer we collectively reach at the end.

People opposed to the scientific consensus that one might read about (a.k.a. "Crackpots") often claim that they're misunderstood, or that the scientific "establishment" is out to get them. These claims are ridiculous on their face. Science is incredibly adversarial. If you have a new theory and you can prove that it's correct (or conversely prove some favorite theory is incorrect), you win. Game over, you win. Doesn't matter who you are or how many awards the other side has. We're all looking for the Next Big Thing. And, we will all be excited regardless of what that thing is. But the trick is that you have to show how to prove that your theory is correct. I think this is a point about science that the public in general doesn't get.

So, to the point: which ideas are crap and which ones are good? How's the public to know? And more importantly, how can I tell people in the most definitive terms that I think their theory is crap, without putting up $10,000 for a loss?

In the last couple years, the idea of Prediction Markets has become popular. The idea is that by creating a market, the average "wisdom of the crowd" becomes apparent (and it turns out crowds are actually damn smart). I looked at several, and I propose Inkling Markets for all your physics needs. Thus, I present to you:

This is a "funny money" market in which you will be given $5000 to invest as you see fit upon signing up for a free account. Those of you that want to really put your money where your mouth is are free to explore other sites, but I could not find one that allowed the flexibility to pose arbitrary questions and then bet on it. Most sites are oriented toward sports or political betting.

26 comments:

Jo
said...

Very nice post. As far as the crackpots and LHC danger is concerned, I do not think that anything will make them beleive the LHC is safe. That is the danger of watching too many blackhole movies i think. Also I wouldn't be surprised in the future if people (crackpots and some others) will start blaming LHC as the cause of future natural disasters ! out of their ignorance.

Yeah the site owner has to approve any new markets, and he complained that my description of the LHC disaster scenario wasn't "quantitative enough". Clearly this guy has too much scientist in him. Hopefully it will show up later today (when the sun rises in Chicago).

On the topic of dark energy (and also the fact that if you prove a new theory right, everybody listens), can I point out:

1. I proved in 1996 and published that there is an approx 10^(-10) ms^(-2) cosmological acceleration of the universe (dark energy) implicit in Hubble's law of recession v = HR. See http://nige.wordpress.com/

2. This mathematical physics proof was observationally confirmed by in 1998 by Perlmutter's supernovae data showing the acceleration which implies dark energy.

3. The "dark energy" is graviton field energy: http://nige.wordpress.com/2008/01/30/book/ or http://nige.wordpress.com/about/ The calculation I give, based on the acceleration of the universe, gives the correct gravity coupling G.

This sort of "prediction" claim for string theory is an example of hype, and is a match between a flawed claim about the spin of the graviton being 2, see http://nige.wordpress.com/2008/01/30/book/ , and string theory. The path integral argument for a rank-2 tensor implying spin-2 gravitons falsely assumes that only two attracting masses are exchanging them. Actually, all the mass in the universe has a gravitational charge, so the gravitons are not being exchanged merely between the two masses you see accelerating together. When you go into the details correctly, http://nige.wordpress.com/2008/01/30/book/ , you find that the exchange of gravitons with distant masses in the universe is stronger and it repels or pushes nearby masses together. The same repulsion predicts the acceleration of the universe accurately on immense cosmological distance scales.

Enjoying the new blog, well done, have listed it on my blog (ANTIMATTER).

I found the sentence below very good, pretty much sums up my take on the public understanding of science:"Scientific consensus is only reached after a significant amount of time has passed, and the experiments and theories have been absorbed into the minds of the practitioners of science. This consensus is really all the public needs to worry about..."

Quite. In Ireland, I was involved in a significant battle in the media concerning the publicity given to a single engineer who felt relativity was wrong...I was very shocked at just how gullible 'sceptical' journalists can beRegards, Cormac

The rules elude me too. I had to have a colleague go to the site and buy/sell some futures so we could figure it out. (I am barred from trading since I created the market) This is a futures market so you sell first and buy later, and this process causes the price (or probability) to move.

The proposal "Is the expansion of the universe accelerating?" is essentially to question several well-established experimental results (in particular supernovae and WMAP). Of course people do question the supernovae...but WMAP is a much more precise measurement. Whether they're using an oversimplified model...maybe...

Questioning experiments (rather than theories) is fine, after all sometimes experimental results "go away". I encourage you to start a market on this, or some variation. You might also be interested in this market betting on Lambda>0.

WMAP gives you an image of the CMB as it looks today, i.e. after it's run through a transfer function (everything between us and the surface of last scattering).

If you assume that:

(1) the original signal looks a certain way (scale-free spectrum produced by single inflaton without any bumps or other features induced e.g. by phase transitions during inflation); and

(2) FRW applies and there are no other significant effects on the transfer function;

then you can run a parameter fit which shows that the result is consistent with what WMAP sees, provided that the universe is flat. Since visible and dark matter do not add up to the critical density, you then assume that the missing energy density is dark energy.

This is at best a check on the internal consistency of the concordance model.

Why do you need all three of direct+indirect+collider detection for the 'dark matter particle' to pay out?

There are heaps of perfectly good particle DM scenarios where detection at least one of these channels is either impossible, or very unlikely. Still if that's the bet you want to make, I guess that just lowers the rational price, or more likely means that the market will never close.

Also, the best evidence for DM comes not from dynamics in galaxies, it is galaxy clusters, and more recently large-scale cosmic structure, that give you (as it were) the silver bullet.

And why does the Higgs mass bet include the condition that 'no other particle beyond the SM are discovered'? Does that mean the bet is immediately null and void if (say) a WIMP candidate pops up?

"Why do you need all three of direct+indirect+collider detection for the 'dark matter particle' to pay out?"

Because astrophysics is hard. Direct says: there exists a weakly coupled particle in the vicinity of earth. Indirect says: a particle exists at densities appropriate to be responsible for e.g. galactic rotation curves. Collider is the precision instrument, but cannot prove that it is creating a particle that has a non-zero density in the universe. Note that right now there exist at least 5 claims of indirect particle evidence (and most are mutually incompatible with each other) and 1 claim of direct detection evidence. Most of these must be wrong... A very heavy DM scenario would be unfortunate. Maybe I should add the caveat that I will close the markets if *I* am convinced, and no one yells loud enough to keep me from closing. Finally, large scale structure and galaxy clusters do not tell me whether DM is a particle.

"And why does the Higgs mass bet include the condition that 'no other particle beyond the SM are discovered'? Does that mean the bet is immediately null and void if (say) a WIMP candidate pops up?"

Yes. The Standard Model does not include a WIMP candidate, and even the most minimal Higgs+WIMP scenario can significantly change the expectations for the Higgs mass. Furthermore the Higgs mass expectations in e.g. SUSY may be different than the SM. And what if there's 2 Higgses?

So if you're a SUSY/DM aficionado, make the other 2 bets and ignore the Higgs mass market. ;)

"As I write this, the odds of extra spacetime dimensions are almost twice those of supersymmetry (which has less than 20%). That's... interesting. And weird."

I don't think the results can be trusted yet. There have been very few bets and in both markets there was an initial bet by someone on that site of 400 and 100 shares for SUSY and ED respectively, which perturbed the market to the current value. (This is a lot more shares than you and I would have by signing up and using the initial $5000).

Also the MH market is still high. I set the initial value at $200 to stimulate betting, and I would expect it to converge near $120 or so. Not enough people are betting.

Anonymous (re: "classical atom"), yes, crap. This is well covered in any quantum mechanics textbook. Also someone should tell him about the W boson, which causes neutron decay. The "classical atom" is known as the Bohr model for the atom, and makes several wrong predictions.

I must say that this blog is very puzzling. Skepticism in general, and debunking false or nonsense scientific or pseudo-scientific theories is a very serious business. Somehow I do not see how the idea of "Future markets," while rather cute, can be considered as a serious tool in this context.

Maybe, to practice, you should try to debunk the naive idea that Future markets of this kind can have any value for gaining insights into physics problems and other scientific problems.

I'm with you all the way except for one thing: you threw "global warming deniers" in with the tobacco/cancer link and the safety of the LHC. I don't want to hijack the thread into a discussion of global warming; I just wanted to comment that I don't think you can show the kind of strong, robust consensus on that issue that you can on the other two, so I don't think it's as good an example for your point as the other two.